Hyper threading versus dual processors

[Kressmark]

Hi,

Not sure if I am in the correct forum but...
If an application is designed and tested to work on an hyper threading system, does that mean that the application automatically will work on dual processor systems as well?

I.e.
Is there a difference between hyper threading and dual processors programming-wise?

/mk

 

[ShackDaddy]

Processors which support hyperthreading basically tell the application that they are dual-procesors, via some instruction stream gymnastics. Applications view them the same way, but dual-processors are actually faster, since they REALLY do what hyperthreading processors only pretend to do. To my knowledge, there is no difference in compatibility. Any software I've heard of that is hyperthread-ready is also dual-processor aware.

There IS a difference programming-wise. To take advantage of hyperthreading technology, I believe programmers have to code for the SSE2 instruction set.

Here's an interesting dialogue about performance gains via hyperthreading:

http://softwareforums.intel.com/ISN/Community/en-US/forums/thread/840389.aspx

ShackDaddy
Shackelford Consulting